Nec Display Solutions, Ltd.

Nec Corporation

Nec Viewtechnology, Ltd.

Yukinori Shioya

Hiroki Tanaka

Michio Kobayashi

Jiro Takami

Kenji Kanzaka

Masao Imai

Tadashi Tani

An image display device has a light source; a power supply section that supplies power to a light source; a cooling fan that cools the light source; a input section; and a control section that controls the cooling fan and the power supply section. If a first lighting mode in which a power value supplied to the light source is a first setting value is designated through the input section, the control section causes the power supply section to supply power that corresponds to the first setting value to the light source and causes the cooling fan to operate.

Image display device and light source cooling method

A projection display apparatus includes: a display element that displays an image; a lamp that illuminates the display element to cause the display element to emit an image light; a variable light intensity element that allows the light emitted from the lamp to pass therethrough, the intensity of light passing through the variable light intensity element being variable; and a light intensity controller that determines whether the display element is at an image mute state in which a full-black image is displayed, or at a normal lighting state other than the image mute state, and when the display element is at the image mute state, reduces the amount of power supplied to the lamp to a level that is lower than that of the normal lighting state to decrease the intensity of light emitted from the lamp, and also decreases the intensity of light that passes through the variable light intensity element.

Projection display apparatus and control method therefor

In an electronic device including a discharge lamp, and a lamp power supply section that supplies power to the discharge lamp, a control section makes the lamp power supply section execute a lamp refresh process of supplying power necessary for generation of a halogen cycle to the discharge lamp at predetermined time intervals during low power operation in which the discharge lamp is lighted with power less than the rated power. Further, the control section records, in a recording section (non-volatile memory), a control instruction which is issued to the lamp power supply section during low power operation.

Electronic device and control method therefor

An image determination section determines whether an input image signal represents a bright image or a dark image. A control section switches between a first lighting mode in which the output of a power supply section is a first power value and a second lighting mode in which the output of power supply section is a second power value based on the determined result of the image determination section. The control section refers to a first table that contains data representing the relationship between the power value of the power supply section and the number of rotations of a cooling fan in the case in which the output of the power supply section is increased from the second power value to the first power value at a constant rate when the second lighting mode is switched to the first lighting mode.

A projection display apparatus comprises a lamp; a display element that modulates light emitted from the lamp according to an amplitude of the image signal, and emits the light as the image light; a light intensity controller that changes a lamp power according to a power changing operation, and, if the changed lamp power is lower than a rated power of the lamp and supplied to the lamp for a certain period of time, increases the lamp power and then reduces the lamp power to an original power, identifies an amplitude of the image signal where an intensity of the image light is constant before and after the change of the lamp power; and an image signal controller that controls the amplitude of the image signal to the identified amplitude, and supplies the display element with the image signal.

An image display device includes a light source; a power supply section that supplies power to light source; a cooling fan that cools the light source; an input section; a drive section that supplies a voltage to cooling fan; a control section that controls drive section and power supply section. The control section sets a first power value for the output of the power supply section and also a first voltage value for the output of the drive section. The control section measures a time at which the light source has been lighted. If the measured value exceeds a threshold, the control section gradually increases the output of the power supply section up to a second power value that is greater than the first voltage value over a predetermined time.

A time-division image projector includes a light source radiating white light, a transmission color wheel, with color filters transmitting light of specific wavelength bands, a reflection element where the normal of the reflecting surface is at an inclination to light irradiated onto transmission color wheel and reflects light of specific wavelengths transmitted by color filters in a different direction, an optical modulation element supplied, in time divisions, with image signals corresponding to light of specific wavelengths reflected by reflection element and modulates, the intensity of light of the specific wavelength bands transmitted by color filters according to image signals, projection lens projecting light emitted from optical modulation element, and a motor linked to an axis of rotation of the transmission color wheel causing the transmission color wheel to rotate in synchronism with the supply of the image signals corresponding to the light of the specific wavelengths.

Reflective time-division image projector having a transmission color wheel

A video projector which can obtain high brightness of a projected image, high color purity and low color shading and which can be downsized and reduce the manufacturing cost is provided. The video projector has: an optical source ; a color selection scanning device for selectively filter a color of a light from the optical source to generate a light flux having a specific color in synchronism with a supplied video signal; a video displaying device for modulating an intensity of the light flux in synchronism with the video signal pixel by pixel to form a modulated image responsive to the video image; an imaging lens disposed between the color selection scanning device and the video displaying device , for imaging an intensity distribution and a color distribution of the light flux outgoing from the color selection scanning device on a surface of the video displaying device ; and a projecting lens for projecting the modulated image formed by the video displaying device

Video projector

Reflective time-division image projector

An optical system for a liquid crystal projector in which the deterioration of the contrast of a projection screen is prevented. The optical system, comprising: a light source 1 for emitting a white light, an optical divider 4, 5 for dividing said white light into red, green and blue lights, a liquid crystal display panel 17, 18, 19 for modulating each of said red, green and blue light, a polarizer 14, 15, 16 for polarizing each of said modulated red, green and blue light, an optical synthesis element 21 for synthesizing each of said polarized red, green and blue light, and a green-light removing element 23, 24, 25 for removing green light disposed between said liquid crystal display panel for said blue light and said color synthesis element. The green-light removing element 23, 24, 25 removes is provided between the blue-light modulating LCD panel 19 and the color synthesis element 21. Therefore the deterioration of the contrast of the blue-light modulating LCD panel 19 can be prevented.

Optical system for liquid crystal projector

A liquid crystal projector system capable of reducing color variation on a projection screen which may occur when images from two liquid crystal projectors are combined thereon and obtaining a highly even combined image is provided. The two liquid crystal projectors are arranged such that a flat plane containing optical axes of projection lenses of these liquid crystal projectors becomes in parallel to a minor side direction of the projection screen.

Projector system using two liquid crystal projectors

First polarizing beam splitters have respective first polarization separating surfaces arranged perpendicularly to each other. Each of the first polarization separating surfaces transmits the P-polarization component of a light beam emitted from a light source and reflects its S-polarization component. Each of first light beam reflecting elements reflects the S-polarization component reflected by the first polarization separating surface and a light beam directly inputted from the light source. Second polarizing beam splitters have respective second polarization separating surfaces, each of which transmits the P-polarization component of the light beam inputted from the light source and reflected by the first light beam reflecting element and reflects the S-polarization component. Each of second light beam reflecting elements reflects toward a liquid crystal display device the P-polarization component transmitted from the second polarization separating surface. Phase plates convert the S-polarization components that have been separated by the first and second polarizztion separating surfaces to P-polarization components by rotating their polarization directions by 90.degree..

Projection type liquid crystal display apparatus using multiple

In a projector comprising three image forming devices, disposed between a separation optical section and a combination optical section, for processing a red, a green, and a blue light beams, at least one of the three image forming devices comprises a polarization direction converting means, such as a halfwave plate for converting polarization direction for one of the red, the green, and the blue image light beams so that one of a color combining dichroic mirrors has a cutoff wavelength of spectral characteristic which shifts toward outside for one of the red, the green, and the blue central wavelengths from that of one of a color separating dichroic mirrors. The halfwave plate may be disposed in a light-leaving side of at least one of the three image forming devices.

Growing community of inventors

Tokyo, Japan

Yukinori Shioya